Keating: Russians provided detailed information about Tsarnaev

MOSCOW — When Russia’s domestic intelligence service notified the FBI and CIA about Tamerlan Tsarnaev in 2011, it provided a detailed warning that the Cambridge resident intended to join an Islamic insurgency in Dagestan, US Representative William R. Keating said Thursday in Moscow after a series of meetings with senior officials of the Russian Federal Security Service.

The officials with the service, known as the FSB, believe that if their warning had been acted on, the Boston Marathon bombings could have been averted, said Keating, a Massachusetts Democrat who was in Moscow as part of a six-member congressional delegation discussing how to improve counterterrorism cooperation.

Keating said that senior Russian counterintelligence officials had shown him detailed information that convinced them that Tsarnaev “had plans to join the insurgency back in” Dagestan.